1. Field of Invention
The present invention relates to the technical field of an active matrix driving system electro-optical device. Particularly, the present invention relates to the technical field of an electro-optical device which includes a pixel electrode and a pixel switching thin film transistor (referred to as xe2x80x9cTFTxe2x80x9d hereinafter), which are provided with electrical conduction therebetween, and a storage capacitor and a light-shielding film which are provided in a laminated structure formed on a substrate.
2. Description of Related Art
In a conventional electro-optical device such as a TFT-driven active matrix driving system liquid crystal device, a scanning signal is supplied to a gate electrode of a TFT through a scanning line to turn the TFT on, and an image signal supplied to a source region of a semiconductor layer through a data line is supplied to a pixel electrode through the region between the source and drain of the TFT. Such an image signal is supplied to each of a plurality of pixel electrodes for only a short time through each of a plurality of TFTs. Therefore, in order to hold the voltage of the image signal supplied through a TFT over a longer time than the time of the on state, a storage capacitor is generally added to each pixel electrode.
When light is incident on at least a portion of a channel region or junction regions between the channel region and source-drain regions, and the source-drain regions adjacent to the junction regions in a semiconductor layer which constitutes the TFT, light excitation occurs to change the transistor properties of the TFT, for example, increase a leakage current in the on state. Therefore, for example, in an electro-optical device of a type in which strong light is incident, such as a transmissive electro-optical device for a projector, in order to prevent such a change in the properties of the TFT with light incidence, a light-shielding film is provided on a counter substrate on the incidence side of incident light to cover the space between the pixel electrodes including the channel region of the TFT, or an opaque wide data line which includes an Al film or the like is formed to cover the channel region. Furthermore, on the outgoing side, a light-shielding film is provided below the TFT to shield light reflected by the back, and returned light such as incident light from another electro-optical device, which passes through a synthesis optical system, in a projector that includes a combination of a plurality of electro-optical devices.
In this type of electro-optical device, improvement in quality of a display image is strongly demanded, and in order to satisfy this demand, it is important that a pixel aperture region of each pixel through which display light is transmitted is widened relative to a non-pixel aperture region through which display light is not transmitted, to increase the pixel aperture ratio while decreasing the pixel pitch, and enlarge a storage capacitor added to each pixel electrode.
The storage capacitor is generally formed by utilizing the non-pixel aperture region, and it is thus basically difficult to form the storage capacitor in the pixel aperture region. Therefore, the non-pixel aperture region where the storage capacitor can be formed is narrowed as the pixel aperture region is widened to increase the pixel aperture ratio. However, there is a problem in which the pixel aperture ratio is decreased as the non-pixel aperture region is widened to enlarge the storage capacitor.
It is also very important to sufficiently shield incident light and reflected light in a channel region of TFT or a region (referred to as the xe2x80x9cadjacent region of channelxe2x80x9d hereinafter) adjacent to the channel region, for example, a lightly-doped region of LDD structure TFT, as described above. Namely, a decrease in the pixel pitch causes significant deterioration in image quality resulting from only a slight change in properties of TFT.
However, a total plane region where a light-shielding film or a film having a light shielding function can be arranged is narrowed by increasing the pixel aperture ratio, thereby causing the problem of causing difficulties in completely shielding TFT from light. Furthermore, a decrease in the pixel pitch causes a problem in which even with incident light or reflected light slightly inclined with the substrate surface, light finally enters the channel region or the adjacent region of channel due to the occurrence of multiple reflection in a laminated structure after oblique incidence. Particularly, when the incidence side is covered with a data line which includes an Al film having high reflectance, shielding against incident light approaches perfection with widening of the data line, but widening the data line conversely causes a problem difficult to resolve in which reflected light is reflected by the side facing TFT or subsequently reflected by the TFT-facing surface of a light-shielding film formed below TFT, and the light is likely to be finally incident on the channel region or the adjacent region of channel. Furthermore, shielding against reflected light approaches perfection with widening of the light-shielding film formed below TFT, but widening the light-shielding film formed below TFT causes a problem difficult to resolve in which oblique incident light is reflected by the inner surface of the light-shielding film, or subsequently reflected by the inner surfaces of the data line, and is likely to be finally incident on the channel region or the adjacent region of channel. Particularly, in an electro-optical device for a projector which uses incident light or reflected light having very high intensity per unit region, the above problems are very important for improving image quality.
The present invention has been achieved at least in consideration of the above problems, and an object of the present invention is to provide an electro-optical device in which a pixel aperture ratio can be increased, a storage capacitor can be enlarged, and a high quality image can be displayed.
Another object of the present invention is to provide an electro-optical device in which a change in properties of pixel switching TFT due to incident light or reflected light can be decreased while increasing the pixel aperture ratio, and a high quality image can be displayed.
(1) In a first exemplary aspect of the present invention, an electro-optical device may include a scanning line formed above a substrate, a data line crossing the scanning line, a thin film transistor connected to the scanning line and the data line, a pixel electrode connected to a drain region of the thin film transistor, and a first storage capacitor formed by a plurality of layers between the scanning line and the data line.
In this exemplary embodiment of the present invention, the first storage capacitor is formed by a plurality of layers between the scanning line and the data line by utilizing the laminated structure to enlarge the storage capacitor, thereby providing an electro-optical device capable of displaying a high quality image.
(2) In another exemplary embodiment of the first aspect of the invention, in the electro-optical device, the first storage capacitor may include a first capacitor electrode, an insulating film facing the first capacitor electrode, and a second capacitor electrode opposed to the first capacitor electrode with the insulating film provided therebetween to serve as a relay film for electrically connecting a drain region of the thin film transistor and the pixel electrode.
In this exemplary embodiment of the present invention, the second capacitor electrode which forms the first storage capacitor is formed as the relay film for electrically connecting the drain region of the thin film transistor and the pixel electrode, whereby the problem of causing a difficulty in electrically connecting the pixel electrode and a semiconductor layer due to a long distance therebetween can be solved. Also, the second capacitor electrode can prevent etching penetration during the formation of a contact hole.
(3) In still another exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the first storage capacitor is formed to overlap with each of the semiconductor layers of the thin film transistor and the scanning line, except the connection region between the source region of the thin film transistors and the data line.
In this exemplary embodiment of the present invention, since the storage capacitor is formed to overlap with each of the semiconductor layers and the scanning line, it is possible to increase the pixel aperture ratio, and to enlarge the storage capacitor.
(4) In a further exemplary embodiment of the first aspect of the present invention, the electro-optical device may further include a second storage capacitor which may include a second capacitor electrode, an insulating film facing the second capacitor electrode, and a third capacitor electrode opposed to the second capacitor electrode with the insulating film provided therebetween and consisting of the same film as the scanning line.
In this exemplary embodiment of the present invention, since the second storage capacitor is formed by using the second capacitor electrode, which forms the first storage capacitor, and the scanning line layer, storage capacitors can be laminated in the thickness direction of the substrate, and even with narrow pixel pitch, a relatively large storage capacitor can be formed in a non-aperture region. In addition, the third capacitor electrode may include the same film as the scanning line, storage capacitors can thus be formed by a laminated structure which may consist of a relatively small number of layers,
(5) In a still further exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the third capacitor electrode is formed in parallel with the scanning line except in the connection region between the drain region of the thin film transistor and the second capacitor electrode.
In this exemplary embodiment of the present invention, since the third capacitor electrode is formed in parallel with the scanning line, a storage capacitor can be formed by utilizing the non-aperture region.
(6) In a further exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the third capacitor electrode is electrically connected to the first capacitor electrode.
In this exemplary embodiment of the present invention, no potential variation occurs between the first capacitor electrode and the third capacitor electrode, whereby the possibility of affecting the properties of the thin film transistors can be prevented.
(7) In a further exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the electrical connection between the third capacitor electrode and the first capacitor electrode is located in a region below the data line.
In this exemplary embodiment of the present invention, the space between the pixel electrodes, which are located below the data line and which cannot be used as an aperture region for each pixel, is used for connecting the third capacitor electrode and the first capacitor electrode, thereby causing an advantage for improving the pixel aperture ratio.
(8) In a further exemplary embodiment of the first aspect of the present invention, in the elcctro-optical device, the third capacitor electrode may include a part of a first capacitor line extending along the scanning line, the first capacitor electrode may include a part of a second capacitor line extending along the scanning line, and the first and second capacitor lines are extended to the periphery of the image display region in which the pixel electrode is arranged, and electrically connected to each other.
In this exemplary embodiment of the present invention, the first capacitor line arranged along the scanning line and including a plurality of third capacitor electrodes, and the second capacitor line arranged along the scanning line and including a plurality of first capacitor electrodes are electrically connected to each other outside the image display region to permit relatively simple and secure electrical connection between the third capacitor electrodes and the first capacitor electrodes through the first and second capacitor lines. Also, contact holes need not be provided for connecting both capacitor electrodes in the image display region, and thus the storage capacitors can be enlarged.
(9) In a further exemplary embodiment of the first aspect of the present invention, the electro-optical device may further include a third storage capacitor comprising the third capacitor electrode, an insulating film facing the third capacitor electrode, and a fourth capacitor electrode opposed to the third capacitor electrode with the insulating films provided therebetween and which may consist of the same film as the semiconductor layer.
In this exemplary embodiment of the present invention, the third storage capacitor is formed by using the third capacitor electrode, which constitutes the second storage capacitor, and the semiconductor layer, and storage capacitors can thus be laminated in the thickness direction of the substrate, thereby permitting the construction of a relatively large storage capacitor in the non-aperture region, even when the pixel pitch is decreased. Also, the fourth capacitor electrode may include the same film as the semiconductor layer, and thus storage capacitors can be constructed by a laminated structure which may include a relatively small number of layers.
(10) In a further exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the fourth capacitor electrode is formed to extend from the drain region of the thin film transistor.
In this exemplary embodiment of the present invention, a storage capacitor can be formed by using the drain region of the thin film transistor.
(11) In a further exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the fourth capacitor electrode is formed in parallel with the scanning line.
In this exemplary embodiment of the present invention, the third capacitor electrode is formed in parallel with the scanning line, and thus storage capacitors can be enlarged by using the non-aperture region.
(12) In a further exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the capacitance of the second storage capacitor is smaller than that of each of the first storage capacitor and the third storage capacitor.
In this exemplary embodiment of the present invention, the second storage capacitor which includes the first capacitor electrode and the third capacitor electrode consisting of the same film as the scanning line is small, and thus capacitors can be formed without affecting error in the operation of the TFT.
(13) In a further exemplary embodiment of the first aspect of the present invention, the electro-optical device may further include a fourth storage capacitor which may include the fourth capacitor electrode consisting of the same film as the semiconductor layer, an insulating film facing the fourth capacitor electrode, and a fifth capacitor electrode arranged opposite to the fourth capacitor electrode with the insulating film provided therebetween, for shielding the semiconductor layer from light.
In this exemplary embodiment of the present invention, the fourth storage capacitor is formed by using the fourth capacitor electrode consisting of the same film as the semiconductor layer, which constitutes the third storage capacitor, and a light-shielding film for shielding the semiconductor layer from light, and storage capacitors can thus be laminated in the thickness direction of the substrate, thereby permitting the construction of a relatively large storage capacitor in the non-aperture region even when the pixel pitch is decreased. Also, the fifth capacitor electrode may include the light-shielding film, and thus storage capacitors can be constructed by a laminated structure which may include a relatively small number of layers. In addition, the light-shielding film is formed to cover the substrate side of at least the channel region, whereby the properties of the thin film transistors can be effectively prevented from being changed by incidence of the returned light from the substrate side on the channel region.
(14) In a further exemplary embodiment of the first aspect of the present invention, in the electro-optical device, the fifth capacitor electrode is electrically connected to the first capacitor electrode in the periphery of the image display region.
In this construction of the present invention, the first capacitor electrode, the fifth capacitor electrode and the third capacitor electrode can be formed with a common potential, thereby permitting the formation of stable storage capacitors.
(15) In a further exemplary embodiment of the first aspect of the present invention, the electro-optical device may further include a fifth storage capacitor which may include the first capacitor electrode, an insulating film laminated on the first capacitor electrode, and a sixth capacitor electrode arranged opposite to the first capacitor electrode with the insulating film provided therebetween to form the pixel electrode.
In this exemplary embodiment of the present invention, the fifth storage capacitor is formed by using the first capacitor electrode, which constitutes the first storage capacitor, and the pixel electrode, and storage capacitors can thus be laminated in the thickness direction of the substrate, thereby permitting the construction of a relatively large storage capacitor in the non-aperture region even when the pixel pitch is decreased. Also, the sixth capacitor electrode may include the pixel electrode, and thus storage capacitors can be constructed by a laminated structure consisting of a relatively small number of layers.
(16) In a further embodiment of the first aspect of the present invention, in the electro-optical device, the fifth storage capacitor is formed over the entire periphery of each pixel.
In this exemplary embodiment of the present invention, a storage capacitor can be formed by using the peripheral region of each pixel.
(17) In a second exemplary aspect of the present invention, an electro-optical device may include a scanning line formed above a substrate, a data line formed above the substrate, a thin film transistor connected to the data line, a pixel electrode connected to the drain region of the thin film transistor, a channel region of the thin film transistor on which the scanning line is arranged with a gage insulating film formed therebetween, and a light-shielding conductive film which constitutes a capacitor electrode of a storage capacitor and which is arranged above the scanning line to cover at least the channel region of the thin film transistor.
In this exemplary embodiment of the present invention, the gate insulating film, the scanning line, and the conductive film are laminated in this order on the channel region formed on the substrate. In this laminated structure, the channel region can be shielded by the light-shielding conductive film. Since the conductive film also functions as the capacitor electrode of the storage capacitor, the storage capacitor can be constructed while sufficiently shielding the channel region by a laminated structure that may include a relatively small number of layers.
(18) In another exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the conductive film covers at least portions of the channel region of the thin film transistor, the junction region between a source region and the channel region of the thin film transistor, the junction region between the drain region and the channel region of the thin film transistor, and source and drain regions adjacent to the respective junction regions.
In this construction of the present invention, at least portions of the channel region, the junction regions between the source-drain regions and the channel region, and the source-drain regions adjacent to the junction regions are covered with the conductive film, and it is thus possible to shield even the lightly-doped region of the thin film transistor having, for example, a LDD structure, from incident light, thereby permitting a further decrease in changes in the properties of the thin film transistors.
(19) In still another embodiment of the second aspect of the present invention, in the electro-optical device, the storage capacitor may include a first conductive film which forms one of capacitor electrodes of the storage capacitor, and a second conductive film which forms the other capacitor electrode thereof, the second conductive film electrically connecting a semiconductor layer constituting the drain region to the pixel electrode.
In this exemplary embodiment of the present invention, the second conductive film which constitutes the other electrode of the storage capacitor also functions as a conductive film for relaying the drain region to the pixel electrode, and it is thus possible to prevent etching penetration during the formation of a contact hole for connecting the pixel electrode and the drain region. Namely, the drain region can be connected to the second conductive film through the contact hole formed on the drain region, and the pixel electrode can be connected to the second conductive film through the contact hole formed on the second conductive film to require the two types of contact holes, whereby the etching depth can easily be controlled because of the shortness of the contact holes to prevent the penetration.
(20) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the second conductive film covers at least portions of the channel region of the thin film transistor, the junction region between a source region and the channel region of the thin film transistor, the junction region between the drain region and the channel region of the thin film transistor, and the source and drain regions adjacent to the respective junction regions.
In this exemplary embodiment of the present invention, the channel region is shielded from light by the scanning line arranged above the channel region, and the first conductive film, and further shielded by the second conductive film arranged between the scanning line and the first conductive film, and thus the channel region can be shielded by triple films to further increase the effect of shielding the channel region.
(21) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the channel region is covered with the data line arranged above the first conductive film with an insulating film provided therebetween.
In this exemplary embodiment, since the channel region is shielded by the scanning line formed thereon, and the first conductive film, and further shielded by the second conductive film and the data line arranged thereon, light-shielding can be performed with quadruple films, thereby further increasing the effect of shielding the channel region. Furthermore, since the data line is arranged above the first conductive film, an increase in temperature due to light absorption by the first conductive firm can be suppressed.
(22) In a further exemplary embodiment of the second aspect of the present invention, the electro-optical device may further include a third conductive film which may consist of the same film as the scanning line, and which is arranged opposite to the second conductive film with an interlayer insulating film provided therebetween.
In this exemplary embodiment of the present invention, a storage capacitor can be formed by overlapping the first and second conductive films, and a storage capacitor can also be formed by arranging the second and third conductive films opposite to each other with the interlayer insulating film provided therebetween, thereby permitting lamination of storage capacitors in the thickness direction of the substrate. Therefore, even when the pixel pitch is decreased, a relatively large storage capacitor can be formed in the non-aperture region. Since the third conductive film consists of the same film as the scanning line, the storage capacitors can be formed by a laminated structure that may include a relatively small number of layers.
(23) In a further exemplary embodiment of the second aspect of the present invention, the electro-optical device may further include a fourth conductive film which may consist of the same film as the drain region, and which is arranged opposite to the third conductive film with the gate insulating film provided therebetween.
In this exemplary embodiment of the present invention, since the fourth conductive film may consist of the same film as the drain region is arranged opposite to the third conductive film with the gate insulating film provided therebetween, thereby permitting further lamination of a storage capacitor in the thickness direction of the substrate. Namely, the storage capacitor formed by overlapping the first and second conductive films, the storage capacitor formed by overlapping the second and third conductive films, and the storage capacitor formed by overlapping the third and fourth conductive films enable lamination of storage capacitors in the thickness direction of the substrate. Therefore, even when the pixel pitch is decreased, a relatively large storage capacitor can be formed in the non-aperture region. Since the fourth conductive film may consist of the same film as the drain region, the storage capacitors can be formed by a laminated structure that may include a relatively small number of layers.
(24) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the first conductive film and the third conductive film are electrically connected to each other.
In this exemplary embodiment of the present invention, two storage capacitors can be formed with the second conductive film formed therebetween.
(25) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the second conductive film and the fourth conductive film are electrically connected to each other.
In this exemplary embodiment of the present invention, two storage capacitors can be formed with the third conductive film formed therebetween.
(26) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the first conductive film and the third conductive film are electrically connected to each other, and the second conductive film and the fourth conductive film are electrically connected to each other.
In this exemplary embodiment of the present invention, a storage capacitor is formed in a shape in which the first and the third conductive films, and the second and fourth conductive films, which are arranged in the thickness direction, are engaged in a comb form. Therefore, a larger storage capacitor can be constructed in the non-aperture region.
(27) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the first conductive film covers the channel region, and the data line is formed on the channel region and the adjacent region thereof so as not to project from the first conductive film in a plan view.
In this exemplary embodiment of the present invention, since the first conductive film covers the channel region, even with oblique incident light, incidence on the channel region can be prevented. Furthermore, the data line is formed on the channel region so as not to project from the first conductive film in a plan view. Since the first conductive film is formed with a larger width and located nearer to the channel region, compared with the data line, incidence of oblique light on the channel region can be prevented, and incidence of reflected light from the data line on the channel region can also be prevented.
(28) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the first conductive films may include films having lower reflectance than the data lines.
In this exemplary embodiment of the present invention, since the first conductive film has lower reflectance than that of the data line, when reflected light reaching the channel region due to oblique returned light, or multiple reflected light is reflected by the lower surface of the first conductive film, as in the present invention, incident light can be attenuated by an amount corresponding to a decrease in reflectance to suppress the influence of reflected light, as compared with a case in which light is reflected by the lower surface of the data line. Namely, in the present invention, even when reflected light or multiple reflected light from the lower surface of the first conductive film reaches the channel region, the light intensity is decreased, and thus a change in the properties of the thin film transistors due to the reflected light can be suppressed. The channel region can also be sufficiently shielded from oblique incident light by widening the first conductive film.
(29) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, each of the first conductive film and the data line may include a film containing at least Al.
In this exemplary embodiment of the present invention, incident light can be reflected by the data line and the first conductive film to prevent an increase in the temperature of the electro-optical device and decrease the resistance of the first conductive film.
(30) In a further exemplary embodiment of the second aspect of the present invention, the electro-optical device may further include an underlying light-shielding film which is arranged below the semiconductor layer on the substrate and which is formed to cover at least the channel region as viewed from the opposite side of the substrate, and not to project from the first conductive film in a plan view of the channel region and the adjacent region thereof.
In this exemplary embodiment of the present invention, since the scanning line, the first conductive film and the data line are formed above the channel region, the channel region can be prevented from being irradiated with light from above, and the upper and lower side of the channel region can be shielded because the underlying light-shielding film is further arranged below the channel region. Particularly, the underlying light-shielding film covers the channel region, and can thus prevent the channel region from being irradiated with light (returned light or the like) from the opposite side of the substrate. Furthermore, since the underlying light-shielding film is formed not to project from the first conductive film in a plan view of the channel region and the adjacent region thereof, the channel region can be prevented from being irradiated with incident light reflected by the underlying light-shielding film. In addition, even when there is oblique returned light which is likely to be incident on the channel region due to multiple reflection, the returned light is mostly reflected by the first conductive film having low reflectance and then incident on the channel region, and thus attenuated light is incident on the channel region, whereby the channel region can be prevented from being irradiated with light reflected by the data line having high reflectance. Therefore, even when multiple reflection occurs, the influence on the channel region can be significantly suppressed.
(31) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, at least either of the first conductive film and the underlying light-shielding film is made of a high-melting-point metal.
In this exemplary embodiment of the present invention, the first conductive film and the underlying light-shielding film are made of, for example, a single metal, an alloy, a metal silicide, or the like which contains at least one of opaque high-melting-point metals such as Ti (titanium), Cr (chromium), W (tungsten), Ta (tantalum), Mo (molybdenum), Pd (lead), and the like. Therefore, the first conductive film and the underlying light-shielding film can be prevented from being broken or melted by high-temperature treatment. For example, in the use of Al (aluminum) generally used as a material for the data line, the data line has a reflectance of over 80%, while the first conductive film made of a high-melting-point metal such as Ti, Cr, W, or the like, has reflectance significantly lower than the reflectance of the data line, whereby the effect of the present invention can be sufficiently exhibited.
(32) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the first conductive film has substantially the same size as the second conductive film under the data line.
In this exemplary embodiment, since the first conductive film has substantially the same size as the second conductive film, light can be prevented from entering the channel layer due to internal reflection by the first conductive film, and the area of the first conductive film can be increased to enlarge storage capacitors.
(33) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the first conductive film is extended from the image display region in which the pixel electrode is arranged to the periphery thereof, and connected to a constant potential source in the peripheral region.
In this exemplary embodiment, the first conductive film functions not only as the light-shielding film but also as an electrode of the storage capacitor, which functions as a capacitor line, and thus a storage capacitor which may include the capacitor electrode in which the capacitor line is connected to the constant potential source, can be formed in a laminated structure which may include a relatively small number of layers while sufficiently shielding the channel region. In this case, the capacitor electrode may include the first conductive film, or the capacitor electrode and the other capacitor line (lengthy capacitor line) may include a conductive film different from the first conductive film. In addition, the capacitor electrode can be connected to the constant potential source by effectively using the light-shielding region (the non-aperture region of each pixel). As the constant potential source, a constant potential source for peripheral circuits such as a data line driving circuit, a scanning line driving circuit, can be used, and an exclusive constant potential source need not be provided to exhibit good efficiency.
(34) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the third conductive film may include the capacitor line which is extended from the image display region to the periphery thereof along the scanning line, and connected to the constant potential source in the peripheral region, the first conductive film being connected to the capacitor line.
In this exemplary embodiment, the first conductive film is connected to the capacitor line, and thus the potential of the first conductive film can be kept constant through the capacitor line to prevent the situation in which the properties of the thin film transistor are adversely affected by a change in the potential of the first conductive film, even when the first conductive film is arranged near the channel region. When the first conductive film is used as the capacitor line, the potential of the first conductive film can be fixed by the capacitor line, and thus the first conductive film satisfactorily functions as the capacitor electrode.
(35) In a further exemplary embodiment of the second aspect of the present invention, in the electro-optical device, the underlying light-shielding film may include a light-shielding conductive film, and is connected to the capacitor line for each pixel.
In this exemplary embodiment, the underlying light-shielding film is connected to the capacitor line for each pixel, and thus the potential of the underlying light-shielding film can be kept constant through the capacitor line to prevent the situation in which the properties of the thin film transistors are adversely affected by a change in the potential of the underlying light-shielding films, even when the underlying light-shielding film is arranged near the channel region. When the underlying light-shielding film is used as the capacitor electrode, the potential of the underlying light-shielding film can be fixed by the capacitor line, and thus the underlying light-shielding film satisfactorily functions as the capacitor electrode.
(36) In a third exemplary aspect of the present invention, an electro-optical device may include a thin film transistor, a data line electrically connected to a semiconductor layer of the thin film transistor through a first connection portion, a scanning line overlapped with the semiconductor layer of the thin film transistor, a pixel electrode electrically connected to the semiconductor layer of the thin film transistor through a second connection portion, and a light-shielding film arranged in a region including the data line and the scanning line except the first and second connection portions.
In this exemplary embodiment construction of the present invention, a region with a poor contrast ratio produced in the periphery of the pixel electrode can be shielded by the light-shielding film.
(37) In another exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the light-shielding film overlaps with the edge of the pixel electrode.
In this exemplary embodiment of the present invention, the regions including the data line and the scanning line can be shielded by the light-shielding film to define the non-aperture region.
(38) In still another exemplary embodiment of the third aspect of the present invention, the electro-optical device may further include an underlying light-shielding film provided below the semiconductor layer so that at least a portion of the thin film transistor is held between the light-shielding film and the underlying light-shielding film.
In this exemplary embodiment of the present invention, light incidence on the thin film transistor can be prevented by the light-shielding film and the underlying light-shielding film to suppress a change in the properties of the thin film transistor.
(39) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the underlying light-shielding film is extended along either of the data line and the scanning line.
In this exemplary embodiment of the present invention, the light-shielding performance of the non-pixel aperture regions can be increased only by the substrate having the thin film transistor.
(40) In a still further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, an anti-reflection film is formed on at least the side of the underlying light-shielding film opposite to the thin film transistor side thereof.
In this exemplary embodiment of the present invention, when light is incident on the underlying light-shielding film, the anti-reflection film can prevent reflection of the light to the channel region and the region adjacent to the channel region of the thin film transistor.
(41) In a further exemplary embodiment of the third aspect of the present invention, the electro-optical device may further include a conductive relay film for electrically connecting the semiconductor layer and the pixel electrode.
In this exemplary embodiment of the present invention, etching penetration due to the formation of contact holes for connecting the pixel region and the drain region can be prevented.
(42) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the relay film is arranged in a region including the data line and the scanning line except the first connection portion for connecting the semiconductor layer and the data line.
In this exemplary embodiment of the present invention, the light-shielding performance can be improved while securing the first connection portion for connecting the semiconductor layer and the data line.
(43) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the relay film is arranged in the second connection portion between the semiconductor layer and the pixel electrode, which is avoided from the light-shielding film.
In this exemplary embodiment of the present invention, the second connection portion between the semiconductor layer and the pixel electrode, which cannot be shielded by the light-shielding film, can be shielded to completely shield the region along the scanning line.
(44) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the data line is made of a light-shielding material.
In this exemplary embodiment of the present invention, the light-shielding performance can be further improved.
(45) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, a space is formed between the data line and the pixel electrode, and the light-shielding film is arranged in the space.
In this exemplary embodiment of the present invention, a parasitic capacitor between the data line and the pixel electrode can be decreased, and the space therebetween can be shielded by the light-shielding film to define the pixel aperture region.
(46) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the data line is arranged in the first connection portion between the semiconductor layer and the data line, which is avoided from the light-shielding film.
In this exemplary embodiment of the present invention, the first connection portion between the semiconductor layer and the data line, which cannot be shielded by the light-shielding film, can be shielded to completely shield the region along the data line.
(47) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the non-pixel aperture region may include the light-shielding film and the underlying light-shielding film.
In this exemplary embodiment of the present invention, the light-shielding performance of the thin film transistor can be improved by shortening the distance between the light-shielding film and the underlying light-shielding film.
(48) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the scanning line is extended to substantially the center of the non-pixel aperture region.
In this exemplary embodiment of the present invention, if the capacitor electrode which constitutes the storage capacitor need not be made of the same film as the scanning line, the scanning line can be extended to substantially the center of the non-pixel aperture region to improve the light-shielding performance of the channel region of the thin film transistor and the adjacent region thereof.
(49) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, in the periphery of the thin film transistor including the channel region, the relay film is located in a region inward of the light-shielding film, and the underlying light-shielding film is located in a region inward of the relay film.
In this exemplary embodiment of the present invention, light incident from the light-shielding film side is not incident directly on the underlying light-shielding film so that incidence of light reflected by the underlying light-shielding film on the thin film transistor can be decreased.
(50) In a further exemplary embodiment of the third aspect of the present invention, in the electro-optical device, the semiconductor layer is located in a region inward of the data line.
In this exemplary embodiment of the present invention, the semiconductor layer is formed in a region inward of the data line, and thus incidence of light on the semiconductor layer can be decreased. Therefore, the semiconductor layer is not extended along the scanning line, whereby the pitch of the non-pixel aperture regions can be decreased, and the light-shielding performance can be improved.